ng_async.c

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/*
 * ng_async.c
 */
 
/*-
 * Copyright (c) 1996-1999 Whistle Communications, Inc.
 * All rights reserved.
 * 
 * Subject to the following obligations and disclaimer of warranty, use and
 * redistribution of this software, in source or object code forms, with or
 * without modifications are expressly permitted by Whistle Communications;
 * provided, however, that:
 * 1. Any and all reproductions of the source or object code must include the
 *    copyright notice above and the following disclaimer of warranties; and
 * 2. No rights are granted, in any manner or form, to use Whistle
 *    Communications, Inc. trademarks, including the mark "WHISTLE
 *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
 *    such appears in the above copyright notice or in the software.
 * 
 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * Author: Archie Cobbs <archie@freebsd.org>
 *
 * $FreeBSD$
 * $Whistle: ng_async.c,v 1.17 1999/11/01 09:24:51 julian Exp $
 */
 
/*
 * This node type implements a PPP style sync <-> async converter.
 * See RFC 1661 for details of how asynchronous encoding works.
 */
 
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/errno.h>
 
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_async.h>
#include <netgraph/ng_parse.h>
 
#include <net/ppp_defs.h>
 
#ifdef NG_SEPARATE_MALLOC
static MALLOC_DEFINE(M_NETGRAPH_ASYNC, "netgraph_async", "netgraph async node");
#else
#define M_NETGRAPH_ASYNC M_NETGRAPH
#endif
 
/* Async decode state */
#define MODE_HUNT       0
#define MODE_NORMAL     1
#define MODE_ESC        2
 
/* Private data structure */
struct ng_async_private {
        node_p          node;           /* Our node */
        hook_p          async;          /* Asynchronous side */
        hook_p          sync;           /* Synchronous side */
        u_char          amode;          /* Async hunt/esape mode */
        u_int16_t       fcs;            /* Decoded async FCS (so far) */
        u_char         *abuf;           /* Buffer to encode sync into */
        u_char         *sbuf;           /* Buffer to decode async into */
        u_int           slen;           /* Length of data in sbuf */
        long            lasttime;       /* Time of last async packet sent */
        struct          ng_async_cfg    cfg;    /* Configuration */
        struct          ng_async_stat   stats;  /* Statistics */
};
typedef struct ng_async_private *sc_p;
 
/* Useful macros */
#define ASYNC_BUF_SIZE(smru)    (2 * (smru) + 10)
#define SYNC_BUF_SIZE(amru)     ((amru) + 10)
#define ERROUT(x)               do { error = (x); goto done; } while (0)
 
/* Netgraph methods */
static ng_constructor_t         nga_constructor;
static ng_rcvdata_t             nga_rcvdata;
static ng_rcvmsg_t              nga_rcvmsg;
static ng_shutdown_t            nga_shutdown;
static ng_newhook_t             nga_newhook;
static ng_disconnect_t          nga_disconnect;
 
/* Helper stuff */
static int      nga_rcv_sync(const sc_p sc, item_p item);
static int      nga_rcv_async(const sc_p sc, item_p item);
 
/* Parse type for struct ng_async_cfg */
static const struct ng_parse_struct_field nga_config_type_fields[]
        = NG_ASYNC_CONFIG_TYPE_INFO;
static const struct ng_parse_type nga_config_type = {
        &ng_parse_struct_type,
        &nga_config_type_fields
};
 
/* Parse type for struct ng_async_stat */
static const struct ng_parse_struct_field nga_stats_type_fields[]
        = NG_ASYNC_STATS_TYPE_INFO;
static const struct ng_parse_type nga_stats_type = {
        &ng_parse_struct_type,
        &nga_stats_type_fields
};
 
/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist nga_cmdlist[] = {
        {
          NGM_ASYNC_COOKIE,
          NGM_ASYNC_CMD_SET_CONFIG,
          "setconfig",
          &nga_config_type,
          NULL
        },
        {
          NGM_ASYNC_COOKIE,
          NGM_ASYNC_CMD_GET_CONFIG,
          "getconfig",
          NULL,
          &nga_config_type
        },
        {
          NGM_ASYNC_COOKIE,
          NGM_ASYNC_CMD_GET_STATS,
          "getstats",
          NULL,
          &nga_stats_type
        },
        {
          NGM_ASYNC_COOKIE,
          NGM_ASYNC_CMD_CLR_STATS,
          "clrstats",
          &nga_stats_type,
          NULL
        },
        { 0 }
};
 
/* Define the netgraph node type */
static struct ng_type typestruct = {
        .version =      NG_ABI_VERSION,
        .name =         NG_ASYNC_NODE_TYPE,
        .constructor =  nga_constructor,
        .rcvmsg =       nga_rcvmsg,
        .shutdown =     nga_shutdown,
        .newhook =      nga_newhook,
        .rcvdata =      nga_rcvdata,
        .disconnect =   nga_disconnect,
        .cmdlist =      nga_cmdlist
};
NETGRAPH_INIT(async, &typestruct);
 
/* CRC table */
static const u_int16_t fcstab[];
 
/******************************************************************
                    NETGRAPH NODE METHODS
******************************************************************/
 
/*
 * Initialize a new node
 */
static int
nga_constructor(node_p node)
{
        sc_p sc;
 
        sc = malloc(sizeof(*sc), M_NETGRAPH_ASYNC, M_WAITOK | M_ZERO);
        sc->amode = MODE_HUNT;
        sc->cfg.accm = ~0;
        sc->cfg.amru = NG_ASYNC_DEFAULT_MRU;
        sc->cfg.smru = NG_ASYNC_DEFAULT_MRU;
        sc->abuf = malloc(ASYNC_BUF_SIZE(sc->cfg.smru),
            M_NETGRAPH_ASYNC, M_WAITOK);
        sc->sbuf = malloc(SYNC_BUF_SIZE(sc->cfg.amru),
            M_NETGRAPH_ASYNC, M_WAITOK);
        NG_NODE_SET_PRIVATE(node, sc);
        sc->node = node;
        return (0);
}
 
/*
 * Reserve a hook for a pending connection
 */
static int
nga_newhook(node_p node, hook_p hook, const char *name)
{
        const sc_p sc = NG_NODE_PRIVATE(node);
        hook_p *hookp;
 
        if (!strcmp(name, NG_ASYNC_HOOK_ASYNC)) {
                /*
                 * We use a static buffer here so only one packet
                 * at a time can be allowed to travel in this direction.
                 * Force Writer semantics.
                 */
                NG_HOOK_FORCE_WRITER(hook);
                hookp = &sc->async;
        } else if (!strcmp(name, NG_ASYNC_HOOK_SYNC)) {
                /*
                 * We use a static state here so only one packet
                 * at a time can be allowed to travel in this direction.
                 * Force Writer semantics.
                 * Since we set this for both directions
                 * we might as well set it for the whole node
                 * bit I haven;t done that (yet).
                 */
                NG_HOOK_FORCE_WRITER(hook);
                hookp = &sc->sync;
        } else {
                return (EINVAL);
        }
        if (*hookp) /* actually can't happen I think [JRE] */
                return (EISCONN);
        *hookp = hook;
        return (0);
}
 
/*
 * Receive incoming data
 */
static int
nga_rcvdata(hook_p hook, item_p item)
{
        const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 
        if (hook == sc->sync)
                return (nga_rcv_sync(sc, item));
        if (hook == sc->async)
                return (nga_rcv_async(sc, item));
        panic("%s", __func__);
}
 
/*
 * Receive incoming control message
 */
static int
nga_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
        const sc_p sc = NG_NODE_PRIVATE(node);
        struct ng_mesg *resp = NULL;
        int error = 0;
        struct ng_mesg *msg;
 
        NGI_GET_MSG(item, msg);
        switch (msg->header.typecookie) {
        case NGM_ASYNC_COOKIE:
                switch (msg->header.cmd) {
                case NGM_ASYNC_CMD_GET_STATS:
                        NG_MKRESPONSE(resp, msg, sizeof(sc->stats), M_NOWAIT);
                        if (resp == NULL)
                                ERROUT(ENOMEM);
                        *((struct ng_async_stat *) resp->data) = sc->stats;
                        break;
                case NGM_ASYNC_CMD_CLR_STATS:
                        bzero(&sc->stats, sizeof(sc->stats));
                        break;
                case NGM_ASYNC_CMD_SET_CONFIG:
                    {
                        struct ng_async_cfg *const cfg =
                                (struct ng_async_cfg *) msg->data;
                        u_char *buf;
 
                        if (msg->header.arglen != sizeof(*cfg))
                                ERROUT(EINVAL);
                        if (cfg->amru < NG_ASYNC_MIN_MRU
                            || cfg->amru > NG_ASYNC_MAX_MRU
                            || cfg->smru < NG_ASYNC_MIN_MRU
                            || cfg->smru > NG_ASYNC_MAX_MRU)
                                ERROUT(EINVAL);
                        cfg->enabled = !!cfg->enabled;  /* normalize */
                        if (cfg->smru > sc->cfg.smru) { /* reallocate buffer */
                                buf = malloc(ASYNC_BUF_SIZE(cfg->smru),
                                    M_NETGRAPH_ASYNC, M_NOWAIT);
                                if (!buf)
                                        ERROUT(ENOMEM);
                                free(sc->abuf, M_NETGRAPH_ASYNC);
                                sc->abuf = buf;
                        }
                        if (cfg->amru > sc->cfg.amru) { /* reallocate buffer */
                                buf = malloc(SYNC_BUF_SIZE(cfg->amru),
                                    M_NETGRAPH_ASYNC, M_NOWAIT);
                                if (!buf)
                                        ERROUT(ENOMEM);
                                free(sc->sbuf, M_NETGRAPH_ASYNC);
                                sc->sbuf = buf;
                                sc->amode = MODE_HUNT;
                                sc->slen = 0;
                        }
                        if (!cfg->enabled) {
                                sc->amode = MODE_HUNT;
                                sc->slen = 0;
                        }
                        sc->cfg = *cfg;
                        break;
                    }
                case NGM_ASYNC_CMD_GET_CONFIG:
                        NG_MKRESPONSE(resp, msg, sizeof(sc->cfg), M_NOWAIT);
                        if (!resp)
                                ERROUT(ENOMEM);
                        *((struct ng_async_cfg *) resp->data) = sc->cfg;
                        break;
                default:
                        ERROUT(EINVAL);
                }
                break;
        default:
                ERROUT(EINVAL);
        }
done:
        NG_RESPOND_MSG(error, node, item, resp);
        NG_FREE_MSG(msg);
        return (error);
}
 
/*
 * Shutdown this node
 */
static int
nga_shutdown(node_p node)
{
        const sc_p sc = NG_NODE_PRIVATE(node);
 
        free(sc->abuf, M_NETGRAPH_ASYNC);
        free(sc->sbuf, M_NETGRAPH_ASYNC);
        bzero(sc, sizeof(*sc));
        free(sc, M_NETGRAPH_ASYNC);
        NG_NODE_SET_PRIVATE(node, NULL);
        NG_NODE_UNREF(node);
        return (0);
}
 
/*
 * Lose a hook. When both hooks go away, we disappear.
 */
static int
nga_disconnect(hook_p hook)
{
        const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
        hook_p *hookp;
 
        if (hook == sc->async)
                hookp = &sc->async;
        else if (hook == sc->sync)
                hookp = &sc->sync;
        else
                panic("%s", __func__);
        if (!*hookp)
                panic("%s 2", __func__);
        *hookp = NULL;
        bzero(&sc->stats, sizeof(sc->stats));
        sc->lasttime = 0;
        if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
        && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
                ng_rmnode_self(NG_HOOK_NODE(hook));
        return (0);
}
 
/******************************************************************
                    INTERNAL HELPER STUFF
******************************************************************/
 
/*
 * Encode a byte into the async buffer
 */
static __inline void
nga_async_add(const sc_p sc, u_int16_t *fcs, u_int32_t accm, int *len, u_char x)
{
        *fcs = PPP_FCS(*fcs, x);
        if ((x < 32 && ((1 << x) & accm))
            || (x == PPP_ESCAPE)
            || (x == PPP_FLAG)) {
                sc->abuf[(*len)++] = PPP_ESCAPE;
                x ^= PPP_TRANS;
        }
        sc->abuf[(*len)++] = x;
}
 
/*
 * Receive incoming synchronous data.
 */
static int
nga_rcv_sync(const sc_p sc, item_p item)
{
        struct ifnet *rcvif;
        int alen, error = 0;
        struct timeval time;
        u_int16_t fcs, fcs0;
        u_int32_t accm;
        struct mbuf *m;
 
#define ADD_BYTE(x)     nga_async_add(sc, &fcs, accm, &alen, (x))
 
        /* Check for bypass mode */
        if (!sc->cfg.enabled) {
                NG_FWD_ITEM_HOOK(error, item, sc->async );
                return (error);
        }
        NGI_GET_M(item, m);
 
        rcvif = m->m_pkthdr.rcvif;
 
        /* Get ACCM; special case LCP frames, which use full ACCM */
        accm = sc->cfg.accm;
        if (m->m_pkthdr.len >= 4) {
                static const u_char lcphdr[4] = {
                    PPP_ALLSTATIONS,
                    PPP_UI,
                    (u_char)(PPP_LCP >> 8),
                    (u_char)(PPP_LCP & 0xff)
                };
                u_char buf[4];
 
                m_copydata(m, 0, 4, (caddr_t)buf);
                if (bcmp(buf, &lcphdr, 4) == 0)
                        accm = ~0;
        }
 
        /* Check for overflow */
        if (m->m_pkthdr.len > sc->cfg.smru) {
                sc->stats.syncOverflows++;
                NG_FREE_M(m);
                NG_FREE_ITEM(item);
                return (EMSGSIZE);
        }
 
        /* Update stats */
        sc->stats.syncFrames++;
        sc->stats.syncOctets += m->m_pkthdr.len;
 
        /* Initialize async encoded version of input mbuf */
        alen = 0;
        fcs = PPP_INITFCS;
 
        /* Add beginning sync flag if it's been long enough to need one */
        getmicrotime(&time);
        if (time.tv_sec >= sc->lasttime + 1) {
                sc->abuf[alen++] = PPP_FLAG;
                sc->lasttime = time.tv_sec;
        }
 
        /* Add packet payload */
        while (m != NULL) {
                while (m->m_len > 0) {
                        ADD_BYTE(*mtod(m, u_char *));
                        m->m_data++;
                        m->m_len--;
                }
                m = m_free(m);
        }
 
        /* Add checksum and final sync flag */
        fcs0 = fcs;
        ADD_BYTE(~fcs0 & 0xff);
        ADD_BYTE(~fcs0 >> 8);
        sc->abuf[alen++] = PPP_FLAG;
 
        /* Put frame in an mbuf and ship it off */
        if (!(m = m_devget(sc->abuf, alen, 0, rcvif, NULL))) {
                NG_FREE_ITEM(item);
                error = ENOBUFS;
        } else {
                NG_FWD_NEW_DATA(error, item, sc->async, m);
        }
        return (error);
}
 
/*
 * Receive incoming asynchronous data
 * XXX Technically, we should strip out incoming characters
 *     that are in our ACCM. Not sure if this is good or not.
 */
static int
nga_rcv_async(const sc_p sc, item_p item)
{
        struct ifnet *rcvif;
        int error;
        struct mbuf *m;
 
        if (!sc->cfg.enabled) {
                NG_FWD_ITEM_HOOK(error, item,  sc->sync);
                return (error);
        }
        NGI_GET_M(item, m);
        rcvif = m->m_pkthdr.rcvif;
        while (m) {
                struct mbuf *n;
 
                for (; m->m_len > 0; m->m_data++, m->m_len--) {
                        u_char  ch = *mtod(m, u_char *);
 
                        sc->stats.asyncOctets++;
                        if (ch == PPP_FLAG) {   /* Flag overrides everything */
                                int     skip = 0;
 
                                /* Check for runts */
                                if (sc->slen < 2) {
                                        if (sc->slen > 0)
                                                sc->stats.asyncRunts++;
                                        goto reset;
                                }
 
                                /* Verify CRC */
                                if (sc->fcs != PPP_GOODFCS) {
                                        sc->stats.asyncBadCheckSums++;
                                        goto reset;
                                }
                                sc->slen -= 2;
 
                                /* Strip address and control fields */
                                if (sc->slen >= 2
                                    && sc->sbuf[0] == PPP_ALLSTATIONS
                                    && sc->sbuf[1] == PPP_UI)
                                        skip = 2;
 
                                /* Check for frame too big */
                                if (sc->slen - skip > sc->cfg.amru) {
                                        sc->stats.asyncOverflows++;
                                        goto reset;
                                }
 
                                /* OK, ship it out */
                                if ((n = m_devget(sc->sbuf + skip,
                                           sc->slen - skip, 0, rcvif, NULL))) {
                                        if (item) { /* sets NULL -> item */
                                                NG_FWD_NEW_DATA(error, item,
                                                        sc->sync, n);
                                        } else {
                                                NG_SEND_DATA_ONLY(error,
                                                        sc->sync ,n);
                                        }
                                }
                                sc->stats.asyncFrames++;
reset:
                                sc->amode = MODE_NORMAL;
                                sc->fcs = PPP_INITFCS;
                                sc->slen = 0;
                                continue;
                        }
                        switch (sc->amode) {
                        case MODE_NORMAL:
                                if (ch == PPP_ESCAPE) {
                                        sc->amode = MODE_ESC;
                                        continue;
                                }
                                break;
                        case MODE_ESC:
                                ch ^= PPP_TRANS;
                                sc->amode = MODE_NORMAL;
                                break;
                        case MODE_HUNT:
                        default:
                                continue;
                        }
 
                        /* Add byte to frame */
                        if (sc->slen >= SYNC_BUF_SIZE(sc->cfg.amru)) {
                                sc->stats.asyncOverflows++;
                                sc->amode = MODE_HUNT;
                                sc->slen = 0;
                        } else {
                                sc->sbuf[sc->slen++] = ch;
                                sc->fcs = PPP_FCS(sc->fcs, ch);
                        }
                }
                m = m_free(m);
        }
        if (item)
                NG_FREE_ITEM(item);
        return (0);
}
 
/*
 * CRC table
 *
 * Taken from RFC 1171 Appendix B
 */
static const u_int16_t fcstab[256] = {
         0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
         0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
         0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
         0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
         0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
         0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
         0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
         0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
         0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
         0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
         0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
         0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
         0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
         0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
         0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
         0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
         0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
         0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
         0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
         0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
         0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
         0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
         0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
         0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
         0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
         0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
         0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
         0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
         0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
         0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
         0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
         0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};